Browsing by Author "Castanheira, Isabel"
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- 12th IFDC 2017 special issue – Iodine, selenium and iron contents in Portuguese key foods as consumedPublication . Delgado, Inês; Ventura, Marta; Gueifão, Sandra; Coelho, Inês; Nascimento, Ana Cláudia; Silva, José Armando L.; Castanheira, IsabelIodine, selenium and iron are micronutrients essential for thyroid hormone synthesis causing their low plasma levels an additional risk of autoimmune thyroid diseases. A Portuguese TDS pilot study representative of diets in Portugal was carried out, since foods are the main natural sources of these micronutrients. Six hundred and twenty-four samples were collected based on local markets and later analysed in pools of ten meat samples, twenty-seven fish, nine chicken eggs and six cow dairy products. The iodine and selenium contents were determined using ICP-MS after alkaline (iodine) or acid digestion (selenium) and iron by ICP-OES after acid digestion. The highest content of three oligoelements was detected in fish. Meat had lower iodine content and the dairy products lower selenium and iron levels. Sardine presented significant different levels in summer and winter for iodine, and in summer and autumn for selenium, mackerel had diverse contents of iron in summer and autumn. The contribution of salmon and milk for iodine RNI was around 40%, for children and adults. Shrimp is also the food with more selenium, exceeding 1.5 times the % RNI for children and adults females, while iron maximum contribution was observed in meat for children and adult males.
- Abundance of Selenium and Selenoproteins in foods consumed in PortugalPublication . Gueifão, Sandra; Sanches, Diana; Delgado, Inês; Coelho, Inês; Ventura, Marta; Castanheira, IsabelSelenium (Se) is an essential element for human health. Dietary levels in the population are positively correlated to selenium content in foods as consumed. Dietary Reference Intake for Se is 55 μg/day for adult men and women. However, depending on the species, oxidation state and concentration Se can be toxic to human health. Accurate determination of Se content in the diet demands information not only on total Se (tSe) but also on the bioaccessible species presented in food samples [1]. The aim of this work was to evaluate the concentration of tSe and Se species as Selenomethionine (SeMet), Selenite (SeIV) and Selenate (SeVI) in cow milk, cabbage and fish samples consumed in Portugal. Accurate analysis of tSe was carried out by ICP-MS preceded by acid digestion in a closed-vessel microwave system. Several approaches for extraction of Se species from food matrices were studied followed by quantification with HPLC-ICP-MS. The reliable conditions of analytical procedures were achieved with metrological tools operated under the frame of ISO/EN 17025:2005. tSe content ranged from 67 ± 3 ug.kg-1 (cabbage), 161 ± 16 ug.kg-1 (milk) and 988 ± 27 ug.kg-1 (fish). SeMet was major selenium species in milk and fish samples accounting for 85 -90 % of tSe content. In cabbage Se (IV), Se (VI) and (SeMet) were found. The results showed the suitability of analytical procedure to measure tSe and seemed effective to achieve an accurate determination of Se species in these complex matrices. References: [1] Bodnar, M., Szczyglowska, M., Konieczka, P., Namiesnik, J. Methods of Selenium Supplementation: Bioavailability and Determination of Selenium Compounds. Critical Reviews in Food Science and Nutrition. 2016. 56: 36-55.
- A abundância de selenometionina, selenito e selenato em alimentos como consumidosPublication . Sanches, Diana; Gueifão, Sandra; Ventura, Marta; Delgado, Inês; Coelho, Inês; Castanheira, IsabelEste ano (2017), celebra-se o aniversário da descoberta do micronutriente selénio (Se), que foi pela primeira vez identificado pelo químico sueco Jacob Berzelius. Posteriormente, Klaus Schwarz with Foltz provaram que o Se é um nutriente essencial para o normal crescimento e reprodução dos animais e do homem. A maioria das enzimas dependentes de Se, já foram identificadas em várias funções biológicas, tal como regulação da resposta inflamatória, propriedades antioxidantes, através da regulação das espécies reativas de oxigénio (ROS) e do estado redox, e promoção da proliferação/diferenciação das células imunes. A deficiência de Se foi associada, a uma miríade de patologias, sendo de referir o aumento do risco de doenças não transmissíveis como o cancro – incluindo da tiróide – infeções e estados de imunodepressão, infertilidade masculina, diabetes, doenças de Alzheimer e Parkinson, perturbações do humor, doença de Keshan e doença de Kashin-Beck. A carência grave de Se associa-se a disfunção muscular e cardiomiopatia. Estudos no âmbito da relação do Se com o controlo glicémico, Diabetes Mellitus gestacional e hipertrofia adipocitária ainda têm resultados controversos e necessitam de mais estudos para provar a sua correlação. A interdependência entre os teores de selénio presentes nos alimentos e a redução de toxicidade do arsénio são também descritos na literatura em particular nos últimos anos. Segundo o IOM, nos EUA, e outros artigos da literatura referem que a ingestão alimentar recomendada é de 55μg/dia para um adulto. E a dose máxima admissível (UL) é o nível mais alto de ingestão diária de nutrientes suscetível de não representar qualquer risco de efeitos adversos, em quase todos os indivíduos, sendo importante que todos os indivíduos da população sejam aconselhados para não exceder esta dose – 400 μg/dia. Os alimentos são a fonte principal de selénio. Porém a biodisponibilidade deste oligoelemento está dependente da espécie química presente no alimento. Em Portugal existem poucos dados sobre o perfil de selénio nos alimentos. O objetivo deste estudo foi determinar a abundância de selenometionina (SeMet), selenito (Se IV) e selenato (SeVI) em leite e pescado como consumido pelos portugueses. As amostras foram recolhidas seguindo a metodologia adotada no projeto TDS – Exposure. Recorreu-se à técnica hifenada de HPLC-ICP-MS precedida da extração das espécies, por métodos enzimáticos, da matriz alimentar. Os ensaios foram realizados em condições de controlo da qualidade que refletem os requisitos da Norma 17025:2005. A SeMet foi a espécie predominante, em todos os alimentos analisados. No leite foram encontradas ambas as espécies inorgânicas. No pescado o Se (VI) foi a única espécie inorgânica encontrada. Este estudo foi muito importante porque possibilitou conhecer o perfil das espécies de selénio presentes em alimentos como consumidos, sendo um parâmetro que irá permitir estimar o aporte de selénio, com maior rigor. A importância das estratégias analíticas aplicadas para a quantificação e identificação das espécies de selénio serão objeto de estudos futuros.
- Acid liquefaction of potato (Solanum tuberosum) and sweet potato (Ipomoea batatas) cultivars peels – Pre-screening of antioxidant Aactivity total phenolic and sugar contentsPublication . Mateus, Maria Margarida; Ventura, Patrícia; Rego, Andreia; Motta, Carla; Castanheira, Isabel; Bordado, João Moura; dos Santos, Rui GalhanoIn the present study, the liquefaction of both regular and sweet potato peels was conducted to investigate the bio-oil produced, the sugar and total phenolic content, and antioxidant activity. Initially, the bio-oil obtained after liquefaction was partitioned into two different fractions, a hydrophilic fraction and the other consisted of the portion that contained the apolar compounds. Afterward, the samples of the whole bio-oil, aqueous extract, and organic phase of both cultivars were analyzed by attenuated total reflection- Fourier Transform infrared (ATR-FTIR) spectroscopy, hydroxyl number, and acid value. This was done in combination with assessment of the sugar and total phenolic contents and antioxidant activity. The samples demonstrated a considerable content of phenolic moieties in their composition. The antioxidant activity, which was assessed by the 2,2-diphenyl-1-picrylhydrazyl radical method, revealed that the antioxidants of the liquefied products and its extracts were generally better than that of butylated hydroxytoluene. Glucose, sucrose, and maltose were identified and quantified within all of the samples.
- Acrilamida em doçaria PortuguesaPublication . Jesus, Susana; Delgado, Inês; Ramos, Ana; Brandão, Carlos; Félix, Nelson; Castanheira, IsabelA acrilamida é um composto de estrutura vinílica, com propriedades carcinogénicas (Grupo 2A- IARC) que tem vindo a ser identificado, em alimentos processados, desde 2002. Segundo os últimos documentos publicados pela EFSA deve ser prioritário a determinação do teor de acrilamida em produtos de panificação e pastelaria. Este estudo teve como objetivo a determinação da quantidade de acrilamida em doçaria portuguesa. Trinta amostras de doces e pão fabricados em estabelecimentos hoteleiros do Norte, Centro e Sul do País, foram analisadas individualmente por UPLC-MS para quantificação do teor de acrilamida. Os resultados revelaram que de todas as amostras, os biscoitos de caramelo (110 µg/Kg), os biscoitos apertados (218.8 µg/Kg) e os biscoitos gregos (354.9 µg/Kg) são os que não excedem o valor indicativo da EFSA (500 µg/Kg). Quanto às amostras de tortas (686-1084 µg/Kg), pão de deus (994.5 µg/Kg), pastéis (526.7 – 809 µg/Kg) e queques (676 – 1057.7 µg/Kg) verificou-se que contêm maior quantidade de acrilamida quando comparado com o valor encontrado na literatura. No pão de trigo analisado e correspondente a uma receita nacional foi determinado um teor de acrilamida inferior a 600 µg/Kg. Perante os resultados obtidos, podemos inferir que a formação da acrilamida está relacionada com a receita seguida na confeção dos produtos, já que a temperatura de cozedura das massas foi superior a 120 °C. Os resultados analíticos encontrados aconselham à sua combinação com dados de consumo destes alimentos com vista à análise rigorosa da exposição a este contaminante por parte dos consumidores.
- Acrylamide determination in Portuguese food matrices by UPLC-PDA and UPLC-MSPublication . André, Catarina; Delgado, Inês; Jesus, Susana; Castanheira, IsabelThe aim of this study was the determination of acrylamide in Portuguese food matrices thought the development and optimization of a chromatographic method with two different detectors. Acrylamide is classified by the International Agency for Research on Cancer (IARC) as a probable carcinogenic compound and the growing concern in human food is due to the fact that it was found in some foods when processed at high temperatures. Samples were bought randomly in local supermarkets and correspond to foods that suspect to contain high levels of this compound and contribute significantly to human consumption such as bolo do caco, fries, breakfast cereals, biscuits, coffee, coffee substitutes and pastel de nata. Sample preparation involved solid phase extraction. To quantify acrylamide were developed two chromatographic methods, UPLC-PDA and UPLC-MS/MS. The method who proved to be more suitable and quantify unequivocally acrylamide was UPLC-MS/MS. The chosen foodstuff for acrylamide determination presented a dissimilar range of values. Bolo do caco values depends on the cocking procedures. The lowest cooking temperature yield a lower acrylamide content (669 µg/Kg) while with the two samples cooked with the highest temperature the acrylamide content was must higher (1653 µg/Kg). In fries the content of acrylamide found was approximately 365 µg/Kg, while for breakfast cereals it varies between 238 and 187 µg/Kg depending on chocolate content. The content found was 58 µg/Kg for crackers and 203 µg/Kg for gingerbread. Coffee substitutes presented a value 5 times more than the coffee which was the lowest value determined with an acrylamide value of 25 µg/Kg. According to EFSA acrylamide values for pastry are between 75 and 1044 µg/Kg and the content of pastel de nata was 331 µg/Kg. The acrylamide content in all samples of Portuguese products analyzed were below the indicative values published by EFSA and are not considered to be main hazards of concern.
- Acrylamide determination in portuguese foodstuff by UPLC-PDA e UPLC-MS: preliminary resultsPublication . André, Catarina; Agostinho, Joana; Castanheira, Isabel
- Acrylamide mitigation in bakery productsPublication . Jesus, Susana; Delgado, Inês; Brandão, Carlos; Galhano dos Santos, Rui; Castanheira, IsabelThe aim of this study was the determination of acrylamide in Portuguese bakery and its reduction in a bakery product. Acrylamide is considered by the International Agency for Research on Cancer as a carcinogenic compound to animals and probably to humans. For this study a total of 30 samples of god bread, “trouxa filó”, pies, ham and cheese rollings, muffins, pastels, and cookies were randomly collected in several commercial establishments. Sample preparation involved solid phase extraction and for the quantification of acrylamide a ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) was used. The ham and cheese rolling and “trouxa filó” had the highest amount of acrylamide, 3743 µg/kg, and 3862 µg/kg, respectively. The results also showed that caramel cookies, butter cookies, Greek cookies and cocoa cookies do not exceed the EFSA indicative value (500 μg/kg) (EFSA, 2015). Pie samples(686-1084 μg/kg), god's bread(995 μg/kg), pastels(527-809 μg/kg) and muffins(676-1057μg/kg) contain high levels of acrylamide when compared to the values found in the literature for bakery products, 198 μg/kg (Mojska, Gielecińska, Szponar, & Ołtarzewski, 2010). Given the obtained results, tests were carried out in order to reduce the concentration of acrylamide. A bakery product was prepared to which four different reducing agents (A, B, C and D) were individually added. The effect of each agent on acrylamide formation was evaluated. Results showed that mixture B obtained an acrylamide reduction of 5.6%. On the other hand, the remaining mixtures increased the production of the contaminant. Yet, it was found that the decrease obtained with mixture B is still not sufficient since it remains above the indicative value of EFSA. Thus, further studies are necessary in order to achieve a higher percentage of reduction of acrylamide. Progress studies are ongoing with other reducing agents and flours.
- Acrylamide mitigation in rye and oat breadPublication . Jesus, Susana; Delgado, Inês; Brandão, Carlos; Galhano dos Santos, Rui; Castanheira, IsabelBackground and objective(s):Acrylamide is a carcinogenic substance for animals and to humans. The harmful effect of such compound was later confirmed, and recently the acrylamide was considered a neurotoxic and genotoxic substance1. This contaminant has been found in carbohydrate-rich foods since 20022. There are many studies regarding several mitigation strategies, however it is need to change the manufacturing processes3. The aim of the study was to reduce the acrylamide content in bread. Materials and methods:It was selected oat and rye breads which are consumed ones daily by the population. The confection trials of rye and oat breads were made with the addition of 15 polyphenols-rich additives separately. For detection and quantification of acrylamide was used the ultra-efficiency liquid chromatography coupled to a mass detector. Results:In oat bread was found that only one additive allowed 77.8% reduction of acrylamide. Such value was below of the indicative value published by EFSA, 150 μg/kg2. In rye bread was obtained a maximum reduction of 79%. Comparing the rye bread results with the indicative value of EFSA, only one bread was lower than 150 μg/kg2. However, further studies on the quantity of additives added are needed, due to the close results of the indicative value. Discussion and conclusion(s):In general, there was a wide variability in acrylamide levels among the two breads. These differences can be caused by the nutritional composition of each flour. A more detailed study of the mechanism of the reduction of these additives in different nutritional composition flours is, therefore, necessary. References: 1. Claeys, W. et al. Reassessment of the acrylamide risk: Belgium as a case-study. Food Control 59, 628–635 (2016). 2. EFSA. Scientific Opinion acrylamide in Food. EFSA Journal 8, (2015). 3. Pedreschi, F., Mariotti, M. S. & Granby, K. Current issues in dietary acrylamide: Formation, mitigation and risk assessment. J. Sci. Food Agric. 94, 9–20 (2014).
- Adição de Amaranto como Fonte de Folatos Naturais – Efeito da GerminaçãoPublication . Moreira, Tiago; Motta, Carla; Ribeiro, Mariana M.; Castanheira, IsabelO consumo de alimentos ricos em folatos representa um contributo importante na prevenção do desenvolvimento de defeitos do tubo neural. A nível mundial este problema afecta aproximadamente trezentos mil bebés. Entre os alimentos ricos em folatos o amaranto é conhecido elevado valor nutritivo e pelo baixo teor em prolaminas, sendo por isso considerado isento de glúten. E o valor nutricional deste pseudocereal pode ser potenciada pela germinação.